title: Theoretical study on the antioxidant properties of 2'-hydroxychalcones: H-atom vs. electron transfer mechanism.
abstract: The free radical scavenging activity of six 2'-hydroxychalcones has been studied in gas phase and solvents using the density functional theory (DFT) method. The three main working mechanisms, hydrogen atom transfer (HAT), stepwise electron-transfer-proton-transfer (ET-PT) and sequential-proton-loss-electron-transfer (SPLET) have been considered. The O-H bond dissociation enthalpy (BDE), ionization potential (IP), proton affinity (PA) and electron transfer energy (ETE) parameters have been computed in gas phase and solvents. The theoretical results confirmed the important role of the B ring in the antioxidant properties of hydroxychalcones. In addition, the calculated results matched well with experimental values. The results suggested that HAT would be the most favorable mechanism for explaining the radical-scavenging activity of hydroxychalcone in gas phase, whereas SPLET mechanism is thermodynamically preferred pathway in aqueous solution.
authors.affiliation: Chemical and Biological Pharmaceutical Engineering Research Center, Xuzhou Medical College, No.209, Tongshan Road, Xuzhou, Jiangsu, 221004, China. xueyunsheng@xzmc.edu.cn
authors.forename: Yunsheng
authors.initials: Y
authors.lastname: Xue
authors.forename: Youguang
authors.initials: Y
authors.lastname: Zheng
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Wenya
authors.initials: W
authors.lastname: Wu
authors.forename: Ding
authors.initials: D
authors.lastname: Yu
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D047188:Chalcones / Q000737:chemistry*; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry; D008962:Models, Theoretical; D008968:Molecular Conformation; D011522:Protons; D012997:Solvents / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D000975:Antioxidants; D047188:Chalcones; D011522:Protons; D012997:Solvents; D006859:Hydrogen; C013031:2'-hydroxychalcone